Improvement in steam-fower air-brakes



' H. L'. McAVOY. Steamer P'owerAir-Brakes.

Patented April 29, 1873.

W Wm

UNITED STATES PATENT HUGH L. MCAVOY, OF,BALTIMORE, MARYLAND.

IMPROVEMENT IN STEAM-POWER AIR-BRAKES.

Specification forming part of Letters Patent No. 138,339, dated April29, 1573; application filed January 22, 1873.

To all whom it may concern:

Be it known that I, HUGH L. MOAVOY, of the cityof Baltimore and State ofMaryland, have invented certain Improvements in Steam- Power Air-Brakes,of which the following is a specification; and I do hereby declare thatthe same is a full, clear, and exact description of my said invention,reference being had to the accompanying drawing and to the letters ofreference marked thereon.

My invention relates to abrake to be applied to railway cars, andoperated by the compression of atmospheric air or some other elasticaeriform body; and consists, first, in the combination of the steamgenerator or boiler of the locomotive, an air-reservoir, and a brakemechanism, the combination being effected by a steam-pipe connecting thereservoir with the boiler, and an air-pipe joining the said reservoirwith the brake-operating mechanism. The object of this part of myinvention is to produce within the reservoir, as a power to be used inoperating the brakes, a body of air compressed by the direct actionthereupon of the steam passed from the boiler into the reservoir, and,after its production, to convey the compressed air to machineryspecially adapted to set or operate the brakes of the train. Myinvention further consists in the means whereby the said compressed airis applied to the purpose for which it is designed and produced.

In the accompanying drawing forming a part of this specification, FigureI is a longitudinal view of portions of a locomotive, tender, and carhaving my invention thereupon. Fig. II is a part plan of the same. Figs.

III and IV are enlarged views of detached portions of the invention.

Similar letters of reference indicate similar parts of the invention inallthe views.

A is the locomotive-boiler. B is the foot board of the locomotive, uponwhich the en= gineer stands. 0 is the tender, and D a part of a car. Thewheels of the tender and car represented by a, and the shoes andbrakebeams, which operate upon the wheels to check the speed of thetrain, by b. E is an air-reservoir placed upon the tender or locomotivein some convenient position. The upper part of the reservoir isconnected with the steam-space of the boiler by means of the steam-pipec, which pipe is provided with flexible couplings where necessary, andhas a cock or valve, represented by d, in such position as to be withinreach'of the engineer, to be controlled by means of the lever e. Thevalve (1 is of that character usually known as three-way, which, in thiscase, is constructed in such manner that, in one position of the levere, the steam from the boiler flows into the reservoir, and, by alteringthe posit-ion'ot' the lever, the flow of steam may be stopped and thesteam contained in the reservoir discharged through the escape-pipef.The lower portion of the reservoir is connected with the mechanism usedto operate the brakes, and afterward more fully described, by means ofthe pipes represented by h h h. The pipe h is siphonic in form, andconnects the interior of the reservoir, near the bottom, with the pipeh, which extends the entire length of the train, and is provided withflexible couplings at necessary points to prevent injury to the saidpipes and connecting parts, and to allow for the inequality in thedistances between the cars. F F are chambers connected, by means of thepipes h, to the air-pipe h, and are formed by securing the diaphragms kto the concave side of the plate l. These diaphragms, which are made ofgum, leather, or some other flexible material, conform nearly in shapeto the interior surface of the plate I, and are fastened by bolts, whichalso secure the perforated guide-plates l. The diaphra'gms, bypresenting convex surfaces to the compressed air, are susceptible of amore extended movement than flat disks would be under similarcircumstances, besides having a: greater tendency to assume theiroriginal shape when the pressure is removed. G G are stems fastened,air-tight, to the diaphragms 7c, and connect the same with thebrakebeams and shoes directly, as shown in the drawing, or connected tothe ordinary brake levers and rods; in either case no alteration isnecessary in the hand arrangement for operating the brakes, whichremains intact to be used in case of an emergency. The chambers F,facingeach other and operating upon the wheels on the same side of the truckof the car, are shown in Fig. II connected together by the FFIOE.

bolts 0, which serve to take the strain when the brakes are applied, andto keep the said chambers at the desired distance apart.

I will now describe the operation of my improved brake when used by theengineer in checking the speed of the train to which it is attached. Thevalve dis opened by means of the lever 0, so as to admit the steam fromthe locomotive-boiler into reservoir E. The air contained in thereservoir is, by this admission of steam, compressed, which compressionmay be continued until it is equal to the pressure of the steam in theboiler, if necessary. The chambers F being connected with the reservoir,as before described, the compressed air acts upon the diaphragms k,forcing them out, thereby placing a strain on the brake beams and shoesI) and the wheels upon which they operate. wheels, the valve 01 isturned by means of the handle 0, and the confined steam in the reservoirallowed to escape, as before described, when the compressed air attainsits original bulk and pressure and the diaphragms their primarycondition. Thus all strain is removed from the brake beams and shoes,and the wheels are free to turn as before the application of the brakes.The air in the reservoir need not at all times be compressed to the fullextent, as the steam may be shut off when sufficient tension has beenplaced upon the wheels. To regulate the maximum pressure to which thereservoir and connecting parts are to be subjected, when the saidpressure is to be less than that in the boiler, vthe safetyvalve 19 isused, which valve is suitably weighted and placed in a position so as tobe within reach of the engineer. H H are cocks placed in the reservoirand chambers for the purpose of allowing the water of condensation whichmay accumulate to pass off, and also to admit air into the saidreservoir and chambers to supply any deficiency caused by leakage.

in the use of steam from the locomotiveboiler directly as a compressor,and the employment of the flexible diaphragms with their attendant partsas transmitters of motion, it is obvious that a large amount of frictionis dispensed with, which would be unavoidable in the use of the ordinaryappliances, such as When it is desired to release theair-pumps andcylinders fitted with pistons; and that the operation of the brake doesnot depend in any way upon the motion of the engine.

Having thus described my invention, what I claim as new, and desire tosecure by Letters Patent of the United States, is-

1. The combination of the locomotive-boiler, an air-compressingreservoir, a pipe connecting the boiler and reservoir, and a pipe orpipes leading from the said reservoir to a brake-operating mechanism,jointly with the method of compressing the air by the direct action ofthe steam thereon in such reservoir, substantially as herein set forth.

2. The chamber formed by the solid and perforated concave-convex platesl I, having within it the flexible diaphragm is and sliding stem G,connected by the pipes h, It, and h to the reservoir E, substantially asand for the purpose herein specified.

8. A series of two or more of the chambers l 1, connected together andto the reservoir E by the pipes h, h, and h common to the series ofchambers, as set forth, for the purpose specified.

4. The stems G operating directly upon the brake-shoes b, in combinationwith the flexible diaphragms 7c forced outward within the chamber 1 l bythe action of compressed air at the back of the diaphragms, as hereinset forth.

5. The combination of the air-reservoir E, safety-valve 19, pipe 0, cockd, and the boiler of the locomotive, as and for the purpose herein setforth.

6. For the purpose of relieving brakes, the combination of the pipe f,three-way cock d, and reservoir E with the pipes h, h,- and h, leadingto the back of the diaphragms k within the chambers l l, as herein shownand specified.

In testimony whereof I have hereto subscribed my name in the city ofBaltimore this 2lst day of January, A. D. 1873.

HUGH L. MoAVOY.

Witnesses J NO. T. MADDOX, WM. T. HOWARD.

